I am taking a course in the history of the High Middle Ages in Europe, say between 1000AD and 1300. One of the demographic drivers of the Middle Ages is the fact that population, while flat before 1000 and declining after 1300, actually doubled in Europe between 1000 and 1300. One of the key drivers was a very warm period that caused agriculture to flourish.
The funny part was listening to the professor try to present this section to today’s audience. He had to keep saying "I know you may find this hard to believe, but warming was very beneficial to European civilization." It was clear the audience was so programmed to think warming=bad, that listeners had a hard time accepting the historical fact that warming created a boom, including a population boom, in Middle Age Europe.